SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '051aa5bcedf7701607fec4c310ea31fea9f9fae78fc017db0629e8c9584e8bbe' 
  AND token = 'UJaJiIDGwnMqTXmz7rtHBicn7Y6rvaofORJTiEDaLVc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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