SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3db280dfb0bfb6c0af09937619414f261e23dffed99796dd7a7c243b41b36c95' 
  AND token = '/OCTAnHl5fGHKMnDeHTgkRrb8iSssMPRIlXCxgmHC1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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