SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66af5609a15302dd124b69c58f025ad363313a4fbb6cb26961efcc218c0f417c' 
  AND token = 'iDXv5PxhHmTqqcIgerL5GuINrd/4XpKZgHVmkldM4YI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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