SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db30debb29a999b95381b43c9ffd76db73099bfef975f56ce5604782de5f1d92' 
  AND token = 'uUfNVvV4CcarXU22IfDtHPHfBXWB4tfEW2EcbrDAChg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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