SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5288447a7b78fb95dde4806df02c990a84b8b63748e064b50f5761685cd0f19d' 
  AND token = 'dNcf9HXXS0dnrLqL0knkOWpBHbyKK044g7knW8yj5hI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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