SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '426871f397fa11203a950856104b8a4d027ef8d5a6b47709ccf127479a566ad7' 
  AND token = 'kXq7otnndSvoYsDwF7OzK9SjWnzjSUXLQ2CATvZ0Ji8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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