SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '247603436937a9c76c44bf54ab0ffc9e38a8bd26725a7fbfd2434f23fddfafb5' 
  AND token = 'UX67XuAZ7nocNEVLwTnDziL0ydra4gzTB2ZNMAKX6XQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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