SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fab9d8b33ad4b5f2a3ab767c003fb6fc32b2d7ca85e97efa922cb269fa693115' 
  AND token = 'nmhtLgXVelgGsj6ZilYr9uwypEtOS5hB88SMWDQMGn0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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