SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d1dfe2b890919903ad2f4d7911dae2292c5d1fc51fa7da5ddcd17ef13772438' 
  AND token = 'dqF2vW8dYS70wcIusQ3pNXQcUa1GTuR15UylPWQRo8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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