SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9424adc3a942a2800c57f3fcaeb250290461349b0312d589618c6978162e0a73' 
  AND token = 'FtGfTfyfu//rwKSXIYE+TO5QlyQGfgBwtb44BCP7jww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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