SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b7a25c8a551b362480e22406c344788734cca363a88162adb0c042a1c3629f8' 
  AND token = 'eJSvoSpgojO0KXrymTJ5xfjYIK/Y8B+gMqP4gOEq/SA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}