SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ebccf0e7c397359eadecb9696d603b1035b1fd4e766d76c2f50e00b124a1c1a7' 
  AND token = 'S/9T04jjTxfy9ySVUu4E1FtRwb63HuGEqvSUEIJTVd8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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