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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3fdc287e0cd1eb9019018fa21c5c27ff6950ce6084d9ae4fb0557229b7dc7ac' 
  AND token = '/RlyQksMZwMDJ5h4a84wQcSksbzBcW+RyfD31Nj1guc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}