SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f3399cc8de97d9efaafb08558b773105a11fc7ae210b8ce5842f599c1d02d1f' 
  AND token = 'YOKErbEHgHg2WkdNoQk8Fubx4mwdzxSTMK5GAIWQogk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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