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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a18e8ea7d3ce2b6750e1fc1ca01b6e2290a813c21638dc34740eb8553b7bb2d5' 
  AND token = '1x3RTxoi4mOLmgAqjIiaOFuF/fyn6hMesuinrKeBrng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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