SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c1999937953277b8e6df055ca6f6d0ee946883d6fce295de7b9f6fb1e66343f' 
  AND token = 'xS9DrOk7VGsPHap+m1TZ5fDHwy7dPwdzEcrmsKVFMNQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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