SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '740582f23c62c298d1e8c70ddf3c58bef05cf841aa5c69d7ca9a0a5e4803b498' 
  AND token = 'gVw2bFm07Zy4NbV9sFU/+zs6jMya0GL3YYuLJhsnHxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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