SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c58a4900a2cc58abb1a22b6ba1a92c419bceaf052d146438bb8faf7ce3d1dfff' 
  AND token = 'fwSgqj3wAB6BbCXXJNFKm+Fwum3WsheestAW76Xn3Y4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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