SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a231ca1018120c86db624e8432345eb16df8fe2f1ffe4ce6b5bd446807bd899' 
  AND token = '9CbbWnA4cZGymsjE9ggcdEJmYR27sclcOvwMnTwnZTY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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