SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'cd00c9589aa7486f1325d44202058bf153c13878f6da3f0de1d379b4777ab75c' 
  AND token = '+rH5rsD5v/pRUUCSjjN0I1YGri4EtRnHtIVoJLiI6Vo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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