SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c918d41138ad19942b4d3e4c22da921f043f49b70d5171055bd9c5d63f684af4' 
  AND token = 'MBtfNLIwAc1pcK3HtrUaCpTLLOS2prh8sVfTiGLnyo8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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