SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'cdd2ab38ec4082243bc7c42c36e2d80ad5a03d2d807c606d11f5f2da37040c54' 
  AND token = 'tU+hfc4wPyPl9/LPyIpltlwy92BdThWxQ+U4PNi2YYc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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