SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ad97648dd05cf6101cb1feaffedb2a72f6399ef348f4922a8244c648c0ce173' 
  AND token = 'R0wzTQveVFWRMBZsyd0Y0QtzBPprVDOMU9ux0RQKB8w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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