SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae9a2887e5aea00f9a641dcd4c40f7d5e3c129d8bdc0e067a01fc6697cd46879' 
  AND token = 'NkzorhvFh7tJ3hfxRblnYXP3J0igCzO+QvBVEPkSp8c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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