SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35370af92ce7b75ad5ece95f5eed3dafebbcf1b87e8ab1e41b9d19c324732dac' 
  AND token = '5KTYtQf2gPwVCJsnhfI34iNlspcNyyOln6f+finPRUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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