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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c97be77fd7c8a429234ae1bb42b6e5e39a09ff6ec6d4bbaa4ede9ec164de9c5b' 
  AND token = 'kDpTXDf3UJ/KJ/qPYdzOzsTSHyrcDMICtOQDdiu1Avs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}