SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14f2dbcf54d751aed0d50f2b39e71e63e12ecfd45d9e66ff25328cd346931966' 
  AND token = 'z103dSdoboI18IwZGBIUnJMWmzI/X4UKCxxpTMNBjno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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