SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'cf443e39688eb49bb2ad43467befbe7b48566dd149d944b3641b1c0c25b9004a' 
  AND token = 'i6IFdTRyuD5hj8pyBbt9A815eqdK3qeSlvE0MKyJbq4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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