SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '462c8ffebeec7350e6217cc628751ff95ac902a6432e27cb0c0b3bdb4914deab' 
  AND token = '5WCfGCF/XVVzdxKpbLaURohF90JIbgjrKXK6XMQIizc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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