SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd15cde547c536319e0bbfc2c50eb9cff6c8a8c3303d9a9056f8e644bf3242894' 
  AND token = 'zhs7lk4HwZRfj6oLWYCDJzGJvYjHjQ3xqeuQE48RPWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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