SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88f4318cd977bad87ab5c3bf687465aaf8155032f73a764356d1c809ec3cf6f8' 
  AND token = 'yQk5jU/ZTVKv/ErWqEtAXHTQGdwxLX2kp99kejjuwCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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