SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1b604d40a6dc39bbe7aca0c29c4f84a8e2afccab93ef945015cb22e616df755' 
  AND token = 'ok67PUTbxVJbHqHiMucFTGyZEdQUozOpNZeerYmd7q0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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