SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23bd2e504dc21f05bc9db88f433bfb7e13d9a7ae954bc1ece8daa97af16e2364' 
  AND token = '3YOHrkcZ8wH5w1KJ9HodOtTFr1ap8qJ8fr7m2LrqDXc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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