SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '979eab6b7b931cc22f74e0d9548652c5df0c1998f6e5393bd1aa8e4eca1deaed' 
  AND token = '9WDL19Jd1dGVjwsQFHlvC5lAh3/ZjxGB7Jge/52YoEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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