SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6405498d72a14677559ce9e993fd577f8fdb3fbdfcedfe46852d29724d90f0b' 
  AND token = 'mkRuZw7GHfjzUFZmvRy1668SVkKTJacikZZILeoeC1E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00095

JSON explain

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