SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d91adbe31505f52df6180f9323f64df5456a128debf2e5f8849459dcd500689' 
  AND token = 'NxW0BJvm8u9bnPBfFrVQykljBhUMMthqApnuorUh20U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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