SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36607218ad126976ee05bc4b1f5eb3b445493e941cb356ac69e8e5b7b690d4f7' 
  AND token = 'mITR5tYLTb8deWqdBS3uWfNYqmURIdbrxGblPxOiyio=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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