SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35dde902a9b090da488ff71301e83673a1de7c2ea3f5f4a3c477c02c6dbba590' 
  AND token = 'hrAL3O8XTgqxfVzX0iLjIQmuzFfRcpl62jKLqD7RvwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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