SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b87508ef4c48784d7f3208ea99f81933f89c590bdeeb9c5e3df47d80a014509' 
  AND token = 'rJThvZpN+79I/e8PhvjOo+FIZoJYke1qfGeZankYBC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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