SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '756ef399c2d3525dcc1fe9341954328cbd6decb28689a6914b730c0b63ea5bdf' 
  AND token = '7CT5ialkv/1GGEBC/oZJ6az3fRiQGLGUbzOXx++D7BQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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