SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '786051cf5fd8d38e9557060f2905852f8106efdfe3e1dace968f8b3533b43e76' 
  AND token = 'sdqkJ0bKkCegC9pNfIL+rN41aXRg+Vay2Y1Yf4eo/kU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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