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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b12a47f64f6ec0215d7fb76ef0ae6bc79141960fb7014201b87c13e42c4a2c9a' 
  AND token = 'aChzUZt3k9p4akiQ0JCrvqoyS+6kQIEGOUz9mD3VHmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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