SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1989a397f95a0a03a2a948466344714581d4cbe18719083bfcf111c6593404f' 
  AND token = 'PJ/BY8OwOaJD7DuvviPFd/eQKN6dG/Zweq7zDziVgxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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