SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71dc7d08badfa7522eb57f2c5a733aadfd5853788158ccff6b50ccca02cc8efc' 
  AND token = 'PtcbXQ27yniD+PQHEjhGp5a7c+UDwSJaDwfj3/HQuTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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