SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eac440acf202f90745e1abc986caf819314eb5c95d3311f2f4f5ca898cb371b9' 
  AND token = 'MlGyDK6jhB8yHayY59hl0WOYOss97xywvndHyJdQmxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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