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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ac5b8e154e97aef50bc7743ddd6e9f0c1b7b926f00d0b3762afab848bb8eabb' 
  AND token = 'UpMsXpjfH9Qj/193AiLA4tIMuNRhEw9KLQAl6BNYlfM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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