SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '905857051dc6c3d94dce5d771dfd44eba342958431d584483270e34de7fdac9e' 
  AND token = 'ZKA5BLl1EkdNRcbx6DtMJAVuWFBNVvqP3kWzIFlhTu8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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