SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b03262710970c6bcfbedf63b6dce1fd5282e5bb87c900cb5e86cf43a99dbedd4' 
  AND token = 'hncnWSSDnEJdM5ni8uxB2kOq4/xyqMRtcsND4qUzBi4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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