SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1721257b7b8907a150527298abac9c8cda8522c8589186920a83a3f2aacc668d' 
  AND token = 'BCGLOAL5owNoe66TFwIWHmdyZ/TbEOohQeswTKIh8NM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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