SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e9dda59f421c3797330828522d8298bc69abb6a9fc9467fa298f5d874b30d6b' 
  AND token = '2ljbGIBhHWsgX/e6WwcZ2aR4lq8vkvwNf5Um3efef7A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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