SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc0ea0d3e37cb7c02fccfbce5fb9f14ae6cc1b813260f71e3c603614c62e6374' 
  AND token = 'PvMe75BIB/gcy51ggwg9RCKMUyPlEhOcMiYILabrmD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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