SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f555b6ed6d579c8698c0dcf998c88840c1852fa9ec2e0c8f000630405542057' 
  AND token = 'eN+M18Hv4VLfnkOwzFqPKS1AvF6KoN6c/qBADGBundw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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