SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '290efb695ab98b7e3c68f138907d4cef4a56112f07ddbe0abab9560b85706da3' 
  AND token = 'a4YCZLUWDFOVrTnJqyg7LZeMdCLhGSd8QJUF5r9Ptq4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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