SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '662a929ce26b4d259e4585403d2803177498a39dabc46fc397a5fa2715c6a384' 
  AND token = '3ZCtW47uUx/5zQOYsyJoN3DN0kJSeIyqr+zCCuqA0KA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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