SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc97c1011877798814f5a6abe054b161c7dea1fdf1407cc7c4b7c52872a4644c' 
  AND token = 'Hy016aswMhWn3u3hPvGgNnCFASq4uaqWcCHBLe4JD04=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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