SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a4bb3093bedfbac286050c8d464abdc61624e1aedef4e5a45e20e254386a2c7' 
  AND token = 'k2TWPEEUwjTQTTxuHbq8BTv0EuQkb8W+tiST85BJZY0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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