SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b13e70d756f8590916dbaf93b5330e4a68496f45fe9a50b4b46e2985ebd5f64' 
  AND token = 'o/09ZDWeFTwHxhDSx9Zeq/Q999BzZ3Wf8lKX0dmaPLI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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