SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef7c35b64e894a76c6fe21f4278ba775c9869ed2f8d9bac74a6a4d5c507abdd2' 
  AND token = 'Q+ZgA/qUGsDYajYhKxFoSkrVFswMNPdXxHxmSXGpfkI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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