SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e52cfd33518b8ec0b1fc2fb7bcd54f79534976f330758dda39f314b77e730fd' 
  AND token = 'keANJR4HJtZUcfr97a81hp9+uRa3uBJnTf0nht47OnY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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