SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4af693ca8323bd842a33daff53fa34cd5f9d7047235363560cd8dc4652da9d08' 
  AND token = '7RSnojgaUROhwn+fth8qNLKc5f6LKehU6/B0v7pJSx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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