SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa187e37323fb6393e56d757c9244f4390cd38f879088aff2f7f7c77f00ae6ad' 
  AND token = 'afB8d+WvDluvkvhMlIGMwlH0oChkfFcnYV3/nZrP6hk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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