SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '967b39191697942124874d93ed840f5efc743bcde4d2522ccecb414f6214802f' 
  AND token = '13fo8Z+AUhe3v6luftLXRMD5TgSsHwfGDz2jQV5rUBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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