SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38cae4ce4427515500c62cfe393485c5b448f41955b6a1def27ad31194917ac4' 
  AND token = 'l9Qxry8UUqmGNwK3yZmoxMJioXK7KBZKlGJCwd2HwHY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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